1. Field of the Invention
This invention relates to mechanical devices that have a component in which large recoverable distortions are available in non-extruded shapes.
2. Description of the Related Art
Common shape memory alloy (also called SMA) materials such as Nitinol can be shape-set by heating to an annealing temperature while constrained to a shape, and then cooling. For example, a helix may be formed from a straight TiNi wire by winding the wire on a mandrel, securing the ends, heating to 550 deg. C., and cooling. The rates of heating and cooling are not critical in this ‘shape-setting’ process for TiNi, although special characteristics are achieved by holding the temperature constant at specific temperatures.